A wireless network, such as a cellular network, can include an access node serving a number of wireless devices or user equipment in a geographical area covered by a radio frequency transmission of the access node. The access node and the wireless devices may communicate with each other to transmit signals or data using physical resource blocks. Each physical resource block may be associated with a frequency span, such as, for example, 180 kHz. Each physical resource block may include a number of sub-carriers. The sub-carriers are spaced apart by a sub-carrier spacing (hereinafter “SCS”). In some wireless communication systems, such as Long-Term-Evolution (LTE) systems, the sub-carrier spacing is fixed at, e.g., 15 kHz. Fixed sub-carrier spacing imposes restrictions on a system's flexibility in handling dynamically changing demands and communication conditions.
Other communication technologies, such as the fifth generation (5G) New Radio (5G NR) technology, may offer non-fixed sub-carrier spacing in order to increase the flexibility and scalability of the system. For example, the 5G NR community has proposed using a numerology to determine the sub-carrier spacing, allowing the sub-carrier spacing to range from 15 kHz to other spacing values, such as 480 kHz. In 5G NR, the sub-carrier spacing may be calculated from 2″×15 kHz, where i is the value of the numerology. When numerology μ=0, the sub-carrier spacing is 20×15 kHz=15 kHz, when numerology μ=1, the sub-carrier spacing is 21×15 kHz=30 kHz, when numerology μ=2, the sub-carrier spacing is 22×15 kHz=60 kHz, when numerology μ=3, the sub-carrier spacing is 23×15 kHz=120 kHz, and when numerology μ=4, the sub-carrier spacing is 24×15 kHz=240 kHz, and so on.
Although the 5G NR uses different values of the sub-carrier spacing based on the value of the numerology, there is still a need for a system and a method that are capable of dynamically selecting sub-carrier spacing based on the changing conditions of communications and the wireless network, such that the system can be more flexible in serving the users of the wireless network.
Overview
Exemplary embodiments described herein include systems, methods, and processing nodes for dynamically selecting a sub-carrier spacing. An exemplary system for selecting a sub-carrier spacing includes an access node configured to deploy a radio air interface to provide wireless services to a plurality of wireless devices. The access node includes a processor configured to determine a value of at least one parameter relating to at least one of radio frequency impairment, mobility, and service latency. The processor is also configured to compare the value of the at least one parameter with a predetermined threshold. The processor is further configured to select the sub-carrier spacing from a plurality of sub-carrier spacings based on a result of the comparison.
An exemplary method described herein for selecting a sub-carrier spacing includes determining a value of at least one parameter relating to at least one of radio frequency impairment, mobility, and service latency. The method also includes comparing the value of the at least one parameter with a predetermined threshold. The method further includes selecting the sub-carrier spacing from a plurality of sub-carrier spacings based on a result of the comparison.
An exemplary processing node described herein for selecting a sub-carrier spacing. The processing node includes a processor configured to perform operations including determining a value of at least one parameter relating to at least one of radio frequency impairment, mobility, and service latency. The operations also include comparing the value of the at least one parameter with a predetermined threshold. The operations further include selecting the sub-carrier spacing from a plurality of sub-carrier spacings based on a result of the comparison.